REG NASA-LLIS-0019-1991 Lessons Learned - Erroneous Electrical System Drawings and Failure to Verify Deenergization Causing a Potentially Serious Electrical Shock Injury.pdf

1、Lessons Learned Entry: 0019Lesson Info:a71 Lesson Number: 0019a71 Lesson Date: 1991-08-22a71 Submitting Organization: JSCa71 Submitted by: W. CrittendenSubject: Erroneous Electrical System Drawings and Failure to Verify Deenergization Causing a Potentially Serious Electrical Shock Injury Description

2、 of Driving Event: In Building 30 at the Johnson Space Center, a contractor electrician received an electrical shock to the hand and forearm from contacting an energized (480 volt AC) power panel lug. A separate contractor, from a remote location that contained the control devices for the power pane

3、l, had switched off, tagged, and verified all circuits deenergized. An electrical drawing was used to assure all circuits were included in the safing procedure. However, a modification was performed earlier to add a lug set and wiring to the panel that was not routed through the same remote controls

4、 location as the original wires, and was not reflected on the facility master drawing. The injured electrician did not verify the lug was deenergized by testing with a meter or other device. The injury was minor (small entrance and exit burns), but could have resulted in severe injury or death had t

5、he current passed through the torso. Corrective actions included updating the facility drawings and emphasis on enforcement of existing procedures for testing circuits as part of the lockout/tagout process.Lesson(s) Learned: Undocumented drawing changes to hazardous systems (480 volts AC), coupled w

6、ith failure to follow required verification of system deenergization as part of lockout/tagout procedure, can lead to potentially serious injuries to electrical workers.Recommendation(s): System drawings were updated; greater emphasis was applied to enforcing the deenergization verification steps of

7、 existing lockout/tagout procedures.Evidence of Recurrence Control Effectiveness: Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-N/ADocuments Related to Lesson: N/AMission Directorate(s): a71 Exploration Systemsa71 Sciencea71 Space Operationsa71 Aer

8、onautics ResearchAdditional Key Phrase(s): a71 Configuration Managementa71 Energya71 Facilitiesa71 Hardwarea71 Human Resources & Educationa71 Safety & Mission AssuranceAdditional Info: Approval Info: a71 Approval Date: 1993-09-10a71 Approval Name: Ron Montaguea71 Approval Organization: JSC/NS3a71 Approval Phone Number: 281-483-8576Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-